Matrix spacer fastener



P 30, 1958 I M. K. ERIKSEN 2,853,739

MATRIX SPACER FASTENER Filed June 29. 1953 i i i FIG.3

Y INVENTOR. i 3 MIERRILL K.ER|KSEN l 'BY FIG. 2

ATTY.

United States Patent 2,853,739 MATRIX SPACER FASTENER Merrill K. Eriksen, Bay Village, Ohio, assignor, by mesne assignments, to The James C. Heintz Company, Cleveland, Ohio, a corporation of Ohio Application June 29, 1953, Serial No. 364,644

1 Claim. (Cl. 18-18) This inventionrelates to means for locking a matrix spacer in position on a matrix by placing it on top of the matrix and then slidably rotating it on the top of the matrix thereby engaging interlocking means located in part on the matrix and in part on the matrix spacer. The interlocking means are disengaged by slidably rotating the spacer on the matrix in the reverse direction.

It has been customary to provide matrix spacers with matrices for retreading pneumatic tires. A set of matrices without a matrix spacer can be used for only one size of tire. By providing a matrix spacer or, preferably, by providing a series of spacers of different widths the same set of matrices can be used for retreading tires of different Widths. It has been customary to bolt these spacers to one of'the matrices to hold them in place.

According to this invention a matrix spacer is fastened to a matrix by merely placing the spacer on the matrix and then slidably rotating it. Interlocking parts are attached to the matrix and the spacer, and are engaged by such rotation. By reversing the direction of rotation the interlocking parts are turned out of engagement and the spacer may be lifted from the matrix. Such interlocking parts will ordinarily be provided at several places on the matrix and matrix spacer as, for example, at positions located 90 or 120 from one another. 1

Different types of interlocking means may be employed. Ordinarily it will be most satisfactory to locate these interlocking means on the outer or'cylindrical surface of the matrix and spacer. They preferably take the form of a-hook and projecting means engageable by the hook, but a variety of difierent types of interlocking means may be utilized.

The invention is further explained in connection with the accompanying drawings which show matrices with flat top and bottom surfaces and cylindrical walls. These are designed for use on flat platens and may be fastened to the platens by any suitable means. Such an arrangement is most advantageous for matrices which are provided with internal heating means which may be electric or steam. However, this invention is not limited to the use of engaging means such as described, on such matrices, but includes their use on other types of matrices such as those adapted to fit into the concave surface of a platen provided with a steam chest, and other types of tireren'eading matrices.

The invention will be further described in connection with the accompanying drawings, in which- Fig. 1 is a top view, partly broken away, showing the top matrix and the spacer below it, with interlocking means on the outer surfaces thereof;

2- Fig. 2 is a side elevation on the line 2-2 of Fig. 1 showing the interlocking means; and

Fig. 3 is a section on the line 3-3 of Fig. 2. The upper matrix 1 and lower matrix 2 are separated by the spacer 3. The outer diameter of the spacer is slightly greater than the outer diameter of the matrices. The hook 5 is fastened to the spacer and engages the projection 7 of the locking means 8 which is fastened to the lower matrix. The same end is accomplished by having the spacer of the same outside diameter as the matrices and making the upper end of the hook thick enough to set the hook out from the surfaces of the matrix sufliciently to engage the projection 7.

As illustrated, the interlocking means is preferably of the type in which one element reaches out to the other, and this element is preferably located on the spacer. If it were on the matrix, it would extend above its upper face and interfere with the insertion of tires into the mold and their removal therefrom.

The upper matrix 1 is of course fastened to the upper platen of the mold. The lower matrix 2 is fastened to the lower platen, and when a spacer is required this is merely placed concentrically on top of the lower matrix and then turned in the direction of the arrow (Fig. 2) to engage the projection 7 in the hook 5. Figure 1 shows sets of interlocking means on several sides of the mold. All are engaged at the same time, by simple rotation of the spacer. I

When it is desired to remove the matrix spacer it is merely necessary to slidably rotate the spacer in the reverse direction and thus disengage the hook 5 from the projection 7. The spacer is then lifted oh the matrix. It

may be replaced by a spacer of a different size, or the spacer may be omitted entirely.

It is understood that the matrix and spacer shown in the drawings are merely illustrative and that other interlocking or engaging means may be used on matrices and matrix spacers of different designs, all as defined in the claim which follows.

What I claim is:

A matrix for a retreading mold and a matrix spacer thereon, the spacer having hook means attached to the outer diameter thereof at several places, each of said hook means extending below the lower surface of the spacer, said hook means being located in a circle of larger diameter than the outside diameter of the matrix and spaced therefrom, and means fastened to the matrix and spaced to cooperate with the hook means at said several places and substantially filling the space between a portion of said hook means and the matrix, with means projecting laterally therefrom which is engageable in the hook means and disengageable therefrom by sliding rotation of the spacer on the matrix.

References Cited in the file of this patent UNITED STATES PATENTS 680,432 Haase Aug. 13, 1901 2,004,800 Rogers June 11, 1935 2,119,467 Chambers May 31, 1938 2,147,339 Glynn Feb. 14, 1939 2,255,163 Heintz Sept. 9, 1941 2,480,578 Hodges Aug. 30, 1949 

